1. Technical Field
This Patent Document relates three-dimensional packaging techniques, such as for switched mode power modules.
2. Related Art
Three-dimensional semiconductor packages incorporate/stack active and passive circuits/components in a single package. Stacking reduces package footprint, improves power density and simplifies assembly.
One application for three-dimensional packaging is power modules for switched mode power supplies (SMPS), which are mountable as a module to a PCBA (printed circuit board assembly). An example SMPS power module includes: power transistors, a load inductor and a driver IC (integrated circuit). The power transistors, for example, high and low side power FETs (half-bridge) are coupled to the load inductor at a switch node, and switched to control power transfer through the load inductor to the load. The driver IC provides gate drive switching control for the power FETs, including feedback control, to supply regulated power to the load, at a regulated load voltage (on a separate load capacitor).
U.S. Pat. No. 8,760,872 describes a stacked power converter package that includes a half-bridge power FET composite (high and low side FETs attached to a switch-node metal carrier), attached to the underside of a sleeve-wrapped load inductor package operable as a heat sink. The driver IC is packaged separately. The half-bridge power FET composite is designated in this Patent Document as a power block, and described further in the Description below. Basically, the power block assemblage includes vertical high and low side NFETs, attached side-by-side to a metal-carrier acting as a switch node. The high-side FET is fabricated drain-down, with a top-side source attached to the switch-node metal carrier, and an underside drain attached to a input VIN pad/terminal, and the low-side FET is fabricated source-down, with a top-side drain attached to the metal-carrier switch node, and an underside source attached to a ground GND pad. A load inductor is wrapped by a metal sleeve in touch with (basically, coextensive with) the opposite surface of the power block metal carrier, and functions to spread and radiate the heat generated by the switching power FETs.
While this Background information is presented in the context of three-dimensional power module applications, the present Patent Document is not limited to such applications, but is more generally directed to three-dimensional packaging techniques.